5: Expirimental Research Flashcards
Expiriment
A type of study designed specifically to answer the question of whether there is a causal relationship between two variables.
- researchers manipulate, or systematically vary, the level of the independent variable (or, conditions)
- researcher exerts control over, or minimizes the variability in, variables other than the independent and dependent variable (extraneous variables)
Conditions
The different levels of the independent variable to which participants are assigned.
Control
Holding extraneous variables constant in order to separate the effect of the independent variable from the effect of the extraneous variables.
Manipulate
Changing the level, or condition, of the independent variable systematically so that different groups of participants are exposed to different levels of that variable, or the same group of participants is exposed to different levels at different times.
Single Factor Two-Level Design
An experiment design involving a single independent variable with two conditions.
Single Factor Multi-Level Design
When an experiment has one independent variable that is manipulated to produce more than two conditions.
Confounding Variable
An extraneous variable that varies systematically with the independent variable, and thus confuses the effect of the independent variable with the effect of the extraneous one.
- can be limited by holding extraneous variables constant
Treatment
Any intervention meant to change people’s behavior for the better.
Treatment Condition
The condition in which participants receive the treatment.
Control Condition
The condition in which participants do not receive the treatment.
Randomized Clinical Trial
An experiment that researches the effectiveness of psychotherapies and medical treatments.
No-Treatment Control Condition
The condition in which participants receive no treatment whatsoever.
Placebo
A simulated treatment that lacks any active ingredient or element that is hypothesized to make the treatment effective, but is otherwise identical to the treatment.
Placebo Effect
An effect that is due to the placebo rather than the treatment.
Waitlist Control Condition
Condition in which participants are told that they will receive the treatment but must wait until the participants in the treatment condition have already received it.
- potential solution to the placebo issue
Between-Subjects Expiriment
An experiment in which each participant is tested in only one condition.
advantages:
- being conceptually simpler and requiring less testing time per participant
- avoid carryover effects without the need for counterbalancing
Within-Subjects Expiriment
An experiment in which each participant is tested under all conditions.
advantages:
- controlling extraneous participant variables, which generally reduces noise in the data and makes it easier to detect any effect of the independent variable upon the dependent variable
- require fewer participants than between-subjects experiments to detect an effect of the same size
Random Assignment
Means using a random process to decide which participants are tested in which conditions.
Block Randomization
All the conditions occur once in the sequence before any of them is repeated.
Matched-Groups Design
An experiment design in which the participants in the various conditions are matched on the dependent variable or on some extraneous variable(s) prior the manipulation of the independent variable.
Order Effect
An effect that occurs when participants’ responses in the various conditions are affected by the order of conditions to which they were exposed
- primary disadvantage of within-subjects designs
Carryover Effect
An effect of being tested in one condition on participants’ behavior in later conditions.
- includes practice effect, fatigue effect
Practice Effect
An effect where participants perform a task better in later conditions because they have had a chance to practice it.
Fatigue Effect
An effect where participants perform a task worse in later conditions because they become tired or bored.
Context Effect (or Contrast Effect)
Unintended influences on respondents’ answers because they are not related to the content of the item but to the context in which the item appears.
- also includes effect of people guessing the hypothesis (demand characteristic)
Counterbalancing
Varying the order of the conditions in which participants are tested, to help solve the problem of order effects in within-subjects experiments.
- controls the order of conditions so that it is no longer a confounding variable (any overall difference in the dependent variable between the conditions cannot have been caused by the order of conditions)
- if there are carryover effects, it makes it possible to detect them (one can analyze the data separately for each order to see whether it had an effect)
Complete Counterbalancing
A method in which an equal number of participants complete each possible order of conditions.
-ie. possible orders of ABC: 1/6 complete each ABC, BCA, CAB, ACB, BAC, CBA
Complete Counterbalancing
A method in which an equal number of participants complete each possible order of conditions.
-ie. possible orders of ABC: 1/6 complete each ABC, BCA, CAB, ACB, BAC, CBA (can use latin square)
Random Counterbalancing
A method in which the order of the conditions is randomly determined for each participant.
Internal Validity
Refers to the degree to which we can confidently infer a causal relationship between variables.
External Validity
Refers to the degree to which we can generalize the findings to other circumstances or settings, like the real-world environment.
Mundane Realism
When the participants and the situation studied are similar to those that the researchers want to generalize to and participants encounter every day.
- high external validity
Psychological Realism
Where the same mental process is used in both the laboratory and in the real world.
- can have low external validity
Construct Validity
One of the “big four” validities, whereby the research question is clearly operationalized by the study’s methods.
Operationalization
The specification of exactly how the research question will be studied in the experiment design.
Subject Pool
An established group of people who have agreed to be contacted about participating in research studies.
-ie. university psych students
Experimenter Expectancy Effect
When the experimenter’s expectations about how participants “should” behave in the experiment affect how the participants behave.
DOuble-Blind Study
A method to reduce experimenter bias, where neither the participant nor the experimenter is knowledgeable about the condition to which the participant is assigned.
Manipulation Check
Verifying the experimental manipulation worked by using a different measure of the construct the researcher is trying to manipulate.
- if proves that manipulation did not work, that means results are valid to the construct measured (including if they are null)
- better to conduct in a pilot test ot avoid using an invalid manipulation for actual research
Pilot Test
Is a small-scale study conducted to make sure that a new procedure works as planned.
